Hydrofluorocarbons (HFCs), compounds containing only carbon, hydrogen and fluorine, because of their zero ozone depletion potential, are of interest as environmentally attractive alternatives for chlorofluorocarbons (i.e., CFCs) in such established uses as refrigerants, heat transfer media, foam expansion agents, aerosol propellants, solvents, fire extinguishants and power cycle working fluids, among other applications.
Hydrofluorocarbons can be obtained by reacting chlorohalocarbons with HF using various catalysts. For example CHF.sub.2 CHF.sub.2 (i.e., 1,1,2,2-tetrafluoroethane or HFC-134) can be prepared by reacting 1,1,2,2-tetrachloroethane with HF over a fluorination catalyst/agent in the liquid or vapor phase (see Int. Publ. No. WO 93/25506). Normally, excess HF is used to achieve relatively favorable reactor rates. HF may be removed from the halogenated hydrocarbon components of the product mixture using conventional aqueous solution scrubbing techniques. However, the production of substantial amounts of scrubbing discharge can create aqueous waste disposal concerns.
There remains a need for processes utilizing HF in such product mixtures as well as an interest in developing more efficient processes for the manufacture of hydrofluorocarbons.